How does a VoIP adapter work?

VoIP adapters are small, simple devices, but they play an important role for residential VoIP service. We received a lot of inquiries about VoIP adapter. What is it? How does it work? Why is it important? Let’s find out!

What is VoIP Adapter?

A VoIP adapter is a device that converts analog voice signals into digital IP packets for transport over an IP network. A VoIP adapter also converts digital IP packets in analog voice streams.

Standard VoIP adapters connect to analog telephones via an FXS port. The VoIP adapter then connects to your Local Area Network (LAN) with an Ethernet cable via an RJ45 port. Some adapters also feature an FXO port so you can connect to the Publicly Switched Telephone Network (PSTN).

How does a VoIP Adapter work?

Think of VoIP adapters as a bridge between an IP network and an analog station device and/or the PSTN. Depending on where the voice traffic originates from, a VoIP adapter converts voice traffic into the proper form for receipt by the destination network or device:

If the voice traffic originates from an analog telephone or the PSTN, the VoIP adapter will convert the analog voice signal into a digital signal. This signal then is compressed using a codec and broken into a series of packets that will be transferred across the IP network using signaling protocol.

If the voice traffic is from an IP network, the adapter will decompress the digital packets into a digital signal that is converted into an analog signal for receipt by the station device or sent across the PSTN.

Standard Features of a VoIP Adapter

• Compliant with multiple protocols including SIP, H.323 and MGCP
• Support for G.711, G.723.1, G.726, and G.729A voice codecs
• T.38 compliant (for faxing)
• Echo cancellation, Jitter Buffer, VAD and CNG
• Web-based administration/management
• Automatic provisioning via TFTP/HTTP

These are just standard features found in the majority of VoIP adapters. Each VoIP adapter has its own unique differences.

There you have it! Now that you know how a VoIP adapter works, go to our site to see the popular adapters including Cisco SPA122, Obihai OBi302, Grandstream HT503 and more!

Click the button below to download our free VoIP Adapter guide to learn more!